Monitoring eustachian tube opening: preliminary results in normal subjects

Sonometry studies the changes of sound intensities induced by the eustachian tube opening in the external meatus when a constant sound is applied in the nasal cavity. The function of the eustachian tube is not disturbed by the test procedure. An original portable device with a high signal-to-noise ratio has been developed in our lab. This device was able to detect a 6-dB sound pressure level (SPL) signal in a 100-dB SPL noise. Long-duration recordings of auditory tubal openings could be performed. This work presents the data found in normal subjects. One hundred twenty healthy ears were recorded. Eustachian tube openings were detected in 62.5% of the cases. Of the 1777 openings recorded, the average opening duration was 430 ms +/- 183 ms. The average number of eustachian tube openings was 21.7+/-16.4 (for 15 minutes). All swallowing did not necessary open the eustachian tube. This work shows that this new device allows long-duration recording of eustachian tube function in everyday life conditions.